Unsteady Effects on NOx Measurements in Pulse Detonation Combustion

Abstract

Emission measurements from unsteady combustion systems such as Pulse Detonation Combustion (PDC) are challenging due to the inherently large variations in pressure, temperature, composition, and flow velocity of the exhaust gas. Comparison of experimental data is additionally complicated by differences in operating conditions and gas sampling setup between different facilities. Qualitative considerations with regard to the sampling process from PDC, based on one-dimensional simulations, indicate a systematic influence of the sampling setup and extraction process on the resulting concentration measurements. Therefore, operating frequency, sample time, fill time, as well as PDC outlet and probe geometry were varied experimentally in order to assess the degree to which each of these parameters impact the resulting measured $${\rm NO}_{\rm x}$$ NO x in order to better inform researchers of these effects when making measurements. It was shown that measured $${\rm NO}_{\rm x}$$ NO x emissions can vary significantly depending on the choice of these parameters and therefore care must be exercised in order to reduce the influence of the sampling technique when aiming for comparable results.

Research on Optical Diagnostic Method of PDE Working Status Based on Visible and Near-Infrared Radiation Characteristics

“…It is extremely difficult to measure and control the fill fraction with high precision due to unfavorable measurement conditions in harsh environments, such as strong vibration, high temperature when detonation exhaust rushes out, and transient variation in pressure. Recently, laser absorption spectroscopy has been generally developed as a useful tool to record the gas concentration and temperature due to its advantages of extremely fast response speed and extremely high environmental adaptability [14][15][16][17][18][19][20]. Hinckley et al [21] used a DFB laser to measure the temperature in the detonation tube, which provided more direct measurement data to monitor the state of PDE combustion.…”